Microcontact printing is a printing technique that can be used, for example, to generate patterns of functionalizing molecules on a surface of a substrate. The functionalizing molecules include a functional group that attaches to a substrate surface or a coated substrate surface via a chemical bond to form a patterned self-assembled monolayer (SAM). The SAM is a single layer of molecules attached by a chemical bond to a surface and that have adopted a preferred orientation with respect to that surface and even with respect to each other.
A basic method for microcontact printing SAMs involves applying an ink containing the functionalizing molecules to a relief-patterned elastomeric stamp (for example, a poly(dimethylsiloxane) (PDMS) stamp) and then contacting the inked stamp to a substrate surface, usually a metal or metal oxide surface, so that SAMs form in the regions of contact between the stamp and the substrate. Alternatively, the elastomeric stamp can be flat (not containing a relief pattern) and the substrate surface can be relief patterned. Micropatterned organic and inorganic materials printed using microcontact printing methods can potentially provide unique electrical, optical, and/or biological properties to substrates such as metallized polymeric films.
In a manufacturing process the functionalizing molecules should be reproducibly transferred from the stamp to the substrate surface in a desired high-resolution patterned SAM with a minimum number of defects. As microcontact printing speeds increase in roll-to-roll manufacturing processes on a moving web of material, pattern defects such as line blurring and voids should be minimized to ensure accurate SAM pattern resolution and reproducibility.